Elastic fluid turbine rotor and method of making same



v C. STEENSTRLP ELASTIC FLUID TURBINE ROTOR AND METHOD OF MAKING sAuE Filed Feb. 16. 1920 His Attorney.

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Patented Oct. 9, 1 923.

UNITED STATES PATENT OFF-ICE.

CHRISTIAN STEENSTRUP, OF SCHENECTADY, NEW YORK, ASSIGNOR TO GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK.

ELASTIC FLUID TURBINE ROTOR AND METHOD OF MAKING SAME.

Application filed February 16, 1920. Serial No. 359,078.

To all whom it may concern v Be it known that l, CHRISTIAN STEEN- STRUP, citizen of the United States, residing at Schenectady, county of Schenectady, State'of New York, have invented certain new and useful Improvements in Elastic Fluid Turbine Rotors and Methods of Making Same, of which the following is a specification. a.

The present invention relates to elastic fluid turbines and particularly to the rotors or rotor elements of such machines.

The primary object of my invention is to provide an improved rotor structure comprising a blade-carrying element or elements with blades fastened thereto, and an improved method of making such a structure.

A further object of my invention is to provide an improved form of bucket which can be advantageously manufactured at a low cost and which is particularly well adapted V for use in carrying outv my present inven tion.

In carrying out my present. invention, I take a blade-carrying element which may be in the form of a wheel. a drum, a ring, or other desired form, and assemble all the blades thereon in the positions they are to have in the completed rotor. In carrying out this assembling operatiomthe blades need be fastened in position in a temporary -manner'only and this may be accomplished for example, by suitable spacing and clamping means which are removable or by suitable engaging parts between the blade-carrying element and the blades which are sufficiently strong to anchorthe blades firmly in position for the time being. The assembled structure is then placed in a suitable mufllcr and the blades and blade-carrying element permanently faStt ned method as set forth in my co-pending application for Letters Patent Serial No. 354,014,

) filed January 26, 1920, which method I term alloy-uniting or alloy-fastening. As thereurably small, and then while held in such intimate contact, introducing alloying metal i into the joint or joints to thereby form an alloy film binding said parts together.

together by the ers or sheets alloy-united together as shown Various alloying metals may be used in carrying out such method but preferably 1 employ copper, and carry the method out by heating the parts to a suitable temperature in the presence. of a reducing atmosphere, preferably of hydrogen.

My present invention is applicable to rotors or rotor elements for various types of turbines. It is well adapted, for example, for use in building up the blade rings for radial flow turbines, such as turbines of the Ljungstrom type, and for fastening buckets on the wheel of a Curtis turbine, and in the following specification I have particularly illustrated and described such applications of my invention. It is to be understood, however, that my invention is not limited to these particular applications.

In the drawing, Figs. 1 to.13 inclusive illustrate my invention as utilized in building up a blade ring for a radial flow turbine. F'gs. 5 and 6 are side and edge views respectively of three types of rings which may be utilized as blade-carrying elements; Fig. 7 is a perspective view of a piece of bucket stock; Fig. 8 shows a bucket made from a piece of stock as shown in Fig. 7 Fig. 9 is an end view of a bucket as shown in Fig. 8; Fig. 10' shows the manner in which a blade ring is assembled; Fi 11 illustrates a completely assembled b1a(e ring and the manner of alloy-uniting it; Fig. 12 shows a slight modification; F igs. 13 and 14 show an application of my invention to a turbine wheel of the Curtis type; and Fig. 15 illustrates a modification.

In carrying out my'invention, as illustrated in Figs. 1 to 11 inclusive, I first provide a number of suitable rings 20' which may be solidrings, asshown in Figs. 1 and 2 or rings made up from a plurality of layin Figs. 3 and 4 or Figs. 5 and 6. Preferably I employ the-latter arrangement because of its greater stren h and freedom from possible flaws. In igs. 3 and 4 a ring 20 is shown as comprising a plurality Figs. 1 and 2, Figs. 3 and 4;, and I formed, particularly in the manner shown in Figs. 3 and 4L or Figs. 5 and 6, may then be ground down and finished by suitable machine operations to bring it to correct di- IIlGIlSlOIlS. i

-After rings 20 of the-desired form are provided, 1 thenassemble' the blades 25 in correct relation to form a blade ring and fasten the whole together in a temporarymanner, preparatory to alloy-uniting them after'the manner set forth in my aboye referred to application for Letters Batent. Various arrangements of temporary fastening means may be utilized, the essential or holes 26 and forming blades 25 having short projections 27 at their ends which are inserted into such holes. Such blades may be made by taking strips of blade stock as shown in Fig. 7' which stock may be made s by drawing-through suitable dies, cutting it into suitable blade lengths, and then upsetting the ends of the blade length to form the projections 27, at the same time forming also a fastening flange'28, thus providing an enlarged surface for seating against the surfaces of rings 20. An upsettlng operation as just referred to is a comparatively simple matter and may be carried'out in any suitable manner. As a result, blades of this type may be manufactured 'at a low cost. Projections 2-7 are of such size'that they fit tightly holes 26 so that when the blade ring is assembled after the manner shown in Fig.

10, the blades willbe firmly anchored in a temporary manner to the rings with the surfaces to be joined in close contact. holes-26 are spaced apart so as to correctly position the blades on the rings.

After being assembled in theforegoing .manner, the blade ring structure is then alloy-united in accordance with the method set forth in my (Ho-pending patent application already referred to, thereby joining th entire blade ring structure into an integral whole. This alloy-uniting process is carried out by placing the blade ring structure in a muffler 29,-'-="-Fig. 11, to which a-reducmg gas, as hydrogen, is admitted through a pipe 30 and discharged through a pipe 31. The blade ring structure may be placed on a light coating of sand or asbestos 32 on a supporting plate 33, the sand or asbestos being used in order to insure that the ring structure is equally supported at all points of its surface. This i done by pressing the ring down firmly on the sand or asbestoswhich will cause the latter to yield slightly and shift around so as to. come into engage ment with all parts of the adjacent ring The structure surface. On top of the structure indicated at 35, for the same purpose aspointed out in connection with coating 32.

The blade ring structure is then heated to a temperature of about 1140 C. to 1150 C.

in this reducing atmosphere, a suitable amount of copper or either alloying material being provided at desired points. F or this latter purpose some small co per wlres as ay be placed for the. purpose indicated at 36 (Fig. 10) may e put around i the structure, or a small bit of copper may be placed in thebottom of each hole 26 as indicated'at 37, it being onlynecessaryin any event that a small amount of the alloy- 7 ing-metal be provided in the Vicinity of the surfaces to be joined. After the structure has been thus joined into one complete whole it is removed from the mufilef 29 and finished and arranged as found desirable for use in the turbine structure for which it is intended.

A blade ring as just described when used in. a turbine of the Ljungstrom type is supported at one end by an expansion ring, the

other end being free and for this. reason it is necessary that such blade rings be very rigid, particularly ma transverse direction.

.lleretofore, so far as I am' aware; such blade rings have been made by a welding process which has been expensive and re- 'the blades have been welded one at a time first to one blade ring. and then to the other and as there are quite a number of concentric blade rings used in a turbine of this type and some of them quite long, the building up of these blade rings for a complete rotor has been a long and expensive piece of work attended with considerable difficulty. By my improved method all the united at the same time. Thismakes it posv sible to do in a single day work which formerly has 'requlred a very much longer time. 1

In Fig. 12 I have shown a modified zirrangement for initially fastening together the rings and blades. In this arrangement the blades 40 have fiat ends in which are x located holes 41 and in rings 42 are holes 43. The buckets are then fastened to the the same time properly spacing the buckets.

As will be seen from Fig. 14, the bottoms of the buckets are curved b the necessary amount to cause them to fol ow the contour of the wheel rim. After the buckets are initially fastened on the wheel rim, a bucket cover 50 is initially fastened in position by any suitable means such as for example by means of tenons 51. The bucket cover may be made in sections or it may be one continuous piece. The wheel structure as now assembled is then alloy-united, in the manner already referred to thereby permanently uniting the buckets to the wheel rim and the bucket cover to the buckets.

In Fig. 15 I have shown a modification particularly intended for building up blade rings for use with radial flow machines and well adapted for large blade rings. In this arrangement the buckets 55 which may be similar to the buckets shown in Figs. 8 and 9 are attached to rings 56 by the method already described. Rings 56 may be rela' tively thin and may be originally plain rings which are afterwards finished to provide the undercut tongues 57 The rings of individual blades thus formed. may then be built up into a complete blade ring, as shown, for example, in Fig. 11 by joining them together by means of strengthening rings 58 which have grooves in which tongues 57 are located. Such joint may be made by rolling the side of the grooves into engagement with tongues 57.

What I claim as new and desire to secure by Letters Patent of the United States, 152

1. A blade ring comprising a plurality of spaced annular rings and blades located between them and united thereto by a metal having a lower melting point than that of the rings and blades, said rings and blades having engaging parts whichserve initially to hold the blade ring as a whole assembled. 2. A blade ring comprising a plurality of spaced annular rings and blades located between them and united thereto by a metal having a lower melting point than that of the rings and blades, the adjacent faces of said rings being provided with holes and the blades being provided with projections which are located in said holes.

3. A blade ring comprising a plurality of spaced rings and blades located between them and alloy-united thereto, one or more of said spaced rings comprising a plurality of discs of thin material'alloy-united together.

4. In an elastic fluid turbine, a blade ring comprising a plurality of'rings in spaced relation to each other, each ring being made up of a number of thicknesses of metal alloyunited together, the adjacent faces of said rings having circ-umferentially spaced holes therein, and blades located between said rings and alloy-united thereto, said blades being provided with projections which fit into said holes, whereby the blades may be fastened into position on the rings prior to .their being alloy-united thereto.

5. In an elastic fluid turbine, a blade carrying element and a blade united thereto by a metal having a lower melting point than that of the element and blade, said blade having a flanged end which presents an enlarged surface for engagement with the element. I

6. In an elastic fluid turbine, a blade carrying element, blades united thereto by a metal having a lower melting point than that of the element and blades, said blades having flanged ends which present enlarged surfaces for engagement with the element, and means for initially positioning the blades on said blade carrying element.

7. In'an elastic fluid turbine, a blade carrying element having spaced holes, and

blades having projections which fit into said holes and flanged ends which present enlarged surfaces for engagement with the element, said blades being united to the element by a metal having a lower melting point than that of the element and blade. 8. A turbine blade comprising a strip of blade material having a flange at at least one end which provides with the end of the blade an enlarged fastening surface.

9. A turbine blade comprising a strip of blade material having a flange at at least one end which provides with the end of the blade an enlarged fastening surface, and an attaching projection on said end.

10. The method of making a turbine blade for alloy-uniting to a blade-carrying element, which comprises taking a length of blading material and upsetting at least one 2nd of it to form an enlarged flat end surace.

. 11. The method of making a turbine blade for alloy-uniting to a blade-carrying element, which comprises taking a length of blading material and upsetting at least one end of it to'form an enlarged flat end suriace with a short projection extending thererow.

v12. The method of making a blade ring which comprises assembling a plurality of rings and blades in correct relation to each other to form a complete blade rlng structure, temporarily fastening them together,

and then permanently fastening them tocomprising a plurality of parallel reinforcing rings with blade lengths between them which comprises building up the complete blade ring structure, temporarily fastening it together, and then permanently uniting the built up structure by means of an alloying metal having a melting point lower than that ofthe rings and blades.

In witness whereof, I have hereunto set my hand this 13th day of February, 1920.

onms'rran 'STEENSTRUP. 

